The 3;8 chromosomal translocation, t(3;8)(p14.2;q24.1), was described in a family with classical features of hereditary renal cell carcinoma (RCC), i.e., autosomal dominant inheritance, early onset and bilateral disease (see A. J. Cohen, et al., N. Engl. J. Med. 301, 592-595 (1979)). The translocation and RCC segregated concordantly and a follow-up analysis reported the occurrence of thyroid cancer in two translocation carriers with kidney cancer (F. P. Li, et al., Ann. Intern. Med 118, 106-111 (1993)). Frequent 3p loss of heterozygosity (LOH) in sporadic clear-cell RCC led to the initial assumption that a critical tumor suppressor gene would be located at 3p14. Identification of the von Hippel-Lindau (VHL) gene at 3p25, frequently mutated in RCCs, provided an alternative explanation for at least some observed 3p LOH and Van den Berg et al. subsequently reported that region p21 may be a primary target for 3p LOH. (A. van den Berg and C. H. Buys, Genes. Chromosomes. Cancer 19, 59-76 (1997)).
Within 3p14, Ohta et al. identified a putative tumor suppressor gene (TSG), FHIT, which was interrupted in its 5' untranslated region by the 3;8 translocation (M. Ohta, et al., Cell 84, 587-597 (1996)). The human gene, like its yeast homologue, encodes di-adenosine (5', 5"- P.sup.1, P.sup.3 -triphosphate) hydrolase activity. (L. D. Barnes, et al., Biochemistry 35, 11529-11535 (1996)). Several reports have described FHIT alterations in diverse carcinomas using nested reverse transcriptase-PCR (RT-PCR). (M. Ohta, et al., Cell 84, 587-597 (1996); G. Sozzi, et al., Cell 85, 17-26 (1996); L. Virgilio, et al., Proc. Natl. Acad. Sci. U. S. A. 93, 9770-9775 (1996); M. Negrini, et al., Cancer Res. 56, 3173 (1996); G. Sozzi, et al., Cancer Res. 56, 2472-2474 (1996)). Other results, however, have been contradictory.
In fact, several lines of evidence make FHIT an unlikely, or at least suspect, causative gene in the hereditary t(3;8) family. For example, the possibility that FHIT functions as a tumor suppressor is at odds with its activity as a di-adenosine hydrolase, an unprecedented tumor suppressor function (Barnes, L. D., et al., Biochemistry 35, 11529-11535 (1996)). The lack of substantial mutations in tumors combined with the fact that most FHIT abnormalities occur in the presence of wild-type transcripts and result from low-abundance splicing alterations, similar to those seen for TSG101, further argues against FHIT acting as a tumor suppressor (S. Thiagalingam, et al., Cancer Res. 56, 2936-2939 (1996); K. M. Fong, et al., Cancer Res. 57, 2256-2267 (1997); S. A. Gayther, et al., Oncogene 15, 2119-2126 (1997); F. Boldog et al., Hum. Mol. Genet. 6, 193-203 (1997); I. Panagopoulos, et al., Genes. Chromosomes. Cancer 19, 215-219 (1997); and A. van den Berg, et al., Genes. Chromosomes. Cancer 19, 220-227 (1997); A. Latil, et al., Oncogene 16, 1863 (1998)).
Moreover, there is little support for the involvement of FHIT in renal cancers (See, A. van den Berg, et al., Genes Chromosomes Cancer 19, 220-227 (1997); P. Bugert, et al., Genes Chromosomes Cancer 20, 9-15 (1997)). Similarly, the reintroduction of FHIT into tumorigenic cell lines was inconsistent in suppressing tumors, including the fact that a hydrolase "dead" mutant appeared active (Z. Siprashvili, et al., Proc. Natl. Acad. Sci. USA 94, 13771-13776 (1997)). Otterson et al. (J. Natl Cancer Inst. 90, 426-432 (1998)) introduced FHIT into six carcinoma cell lines and observed no effects on proliferation, morphology, cell-cycle kinetics, or tumorigenesis.
In earlier work, the present inventors also identified a series of 3p14 deletions, many not involving FHIT exons, which overlapped FRA3B in various carcinoma cell lines (F. Boldog, et al., Hum. Mol. Genet. 6, 193-203 (1997)). However, spontaneous deletions also were observed in nontumor backgrounds. Thus, the close association of FHIT exon 5 with FRA3B suggested that its loss might be primarily related to genomic instability, in contrast to negative selection during tumor development. Although another 3p14 gene might exist, sequence data totaling 160 kb from FRA3B (F. Boldog, et al., Hum. Mol. Genet. 6, 193-203 (1997)) (plus GenBank updates AF023460 and AF023461), together with 135 kb of nonoverlapping sequence from Inoue et al. (Proc. Natl. Acad. Sci. USA 94, 14584-14589 (1997)), failed to show any additional definitive genes.
It was also noted that FHIT, in one parotid adenoma, underwent fusion with the high mobility group protein gene (HMGIC), the causative gene in a variety of benign tumors (J. M. Geurts, et al., Cancer Res. 57, 13-17 (1997)). That HMGIC was involved in translocations with other unrelated genes indicated that FHIT could be a bystander in the FHIT/HMGIC fusion.
Given this evidence arguing against FHIT as the causative gene in the hereditary t(3;8) family, there remained a need to identify the gene or genes involved in the 3;8 translocation that results in the formation of tumors, especially renal and thyroid cancers. Given the correspondence between the 3;8 translocation and certain tumors, identification of the gene involved in the 3;8 translocation could also have value in the diagnosis of other tumors which result from other types of alterations to the gene involved in the 3;8 translocation.